joshua.mills

Hello all,
I have recently bought a 2003 Honda Civic HX with about 190000 miles. Just yesterday, the temperature gauge started to act strangely... It will fluctuate between the normal operating temperature position and anywhere above that up to the H. Meanwhile, the heater dictates this fluctuation, because it will move up when the heater doesn't work, and it will move down when the heater kicks back in. I haven't looked too much into the problem yet, I just want suggestions of where to start off from and hopefully not have to go through the trouble that I saw other people go through on their threads with similar problems. I tried burping the coolant system as suggested by one of the many forums I looked through, and it seemed to work for at least 20 minutes into the drive afterwards, but started doing the same thing all over again. I checked the coolant level and its over the maximum level.. possibly the doing of the previous owner, but I'm not sure. There was an engine light on when I bought the car which could connect to this problem... Temperature sensor's messed up and won't turn on the fan for the heater? Thank you in advance.

Matt_75

What was/is the engine code?

There's a temp sensor, which sends info to the temp gauge on the dash. There's also a temp switch which tells the fans to turn on when a certain engine operating temperature is reached. The fans turning on have nothing to do with the heater.

They are piece #'s 16 and 17 in the below drawing.

http://www.hondaautomotiveparts.com/...+PUMP+-+SENSOR

Worst case scenario is you have a blown/failed head gasket.

joshua.mills

I am getting the code on the CEL tomorrow, so I will update with what that is. Yes, I understand that there is a temperature sensor that sends the dash info, and that seems to be working properly.. and I haven't learned enough about engines in general yet to know which sensors correspond to components and such. The problem is the fan that moves the heat into the cabin is somehow losing its capability in operating right, because it will go on mostly when I'm moving, and it will lose it again when I'm idling or even at times when I move. And there is no coolant in the oil, and there isn't coolant at my exhaust tip. The head doesn't steam either when the temperature gage approaches H. Is considering the thermostat a possibility? Thanks!

Matt_75

Looking forward to it.

Just trying to educate you about your civic.

So the blower motor under the passenger side/glove compartment area is having an issue? Has absolutely nothing to do with over heating.


The thermostat is a possibility, but not likely with the temperature fluctuation you're describing.

These civics do not have any, of the what you may consider, classic symptoms for a head gasket failure.

IMO, the classic symptoms for these cars having a bad head gasket are overheating, coolant lose in the reserve tank and an overflowing/spraying reserve tank. The gasket seems to mostly fail between the piston cylinder chamber and the water jacket on the block side, which allows coolant to be burnt and a very small, if any, amount of combustion gases in to the coolant. Not noticeable at all.

joshua.mills

About the blower motor, I guess I am not being clear enough. When I have the cabin temperature control **** (on the dashboard) on full heat setting, given the car is warmed up, it only delivers hot air around 50% of the time, and just blows frigid outside air the other 50%. When it is delivering hot air at that point, the temperature gauge will read normal. When it loses the heat and all I feel is cold air, the temperature starts to jump. These two behaviors happen interchangeably, whether I'm idling or driving on the highway.

With the gasket problem you are mentioning, I don't notice any abnormality as far as your description goes. As for the more subtle hints of failure, is there
Something I can do to check that while I'm getting the check engine light figured out today?

I know that your statements are perfectly fine, I just feel that there is some correlation with my cabin heat working on and off, and the temperature gauge rising and falling abnormally. Like it takes no time for the engine to overheat itself at an idle and cool itself down seconds later. I would think the cooling system.. Could the the engine temp gauge rising and falling like nobody's business be connected to a working on and off heat in the cabin through interacting components of the cooling system? You have yet to connect heat not working half the time to what you assume to be a head gasket failure.
CEL May help find the answer.

Matt_75

I missed that your reserve tank was already over the max level in your first post. That was probably caused by combustion gas pressurizing the coolant system and not the previous owner. Symptom of a bad head gasket.

Blowing cold air intermittently or always when heat is on. Symptom of a bad head gasket.

Again, these are symptoms for these particular vehicles.

The CEL probably has nothing to do with your over heating issue, but we'll see when you get it read.

The best way that I was told on here by another experienced forum member is to make sure your coolant levels are full in the radiator and reserve tank and apply about 170 psi of shop air in to each spark plug hole. You will then look for bubbles coming up and out of the radiator and/or reserve tank. If you see any bubbles, that cylinder is where the head gasket is leaking between the water jacket and the cylinder chamber.

If you haven't read it yet, read the Common causes of over heating sticky at the top of this forum page. My experience with my bad head gasket is in there as well. I was very lucky and caught mine early. Most people are in denial about it because of the symptoms they see. They're used to seeing what most people consider to be the "classic symptoms" of a head gasket failure. These cars just don't work that way.

Below is a picture of my head and gasket. You can see it's really only the coating material that gradually wears away and causes the gasket to leak between the cylinder and the water jacket. You can see the discoloration in the cylinder that was burning coolant.







Good luck.

joshua.mills

I got the CEL code, its P1166, some sort of sensor? Anyways, its unrelated.

I admire your enthusiasm for the head gasket being the problem, and it very well could be. I must bring up another scenario though..

I discovered a new symptom as I was driving my car today. I was normally going to leave it alone, but I was curious as to whether the behavior would change. Today, I started it and let it warm up as usual. Next, I drove it around my campus and closely observed the behavior of the temperature gauge & the heat coming through the vents. At low RPMs, the temperature gauge acted up the most, but it climbed no more than 1/2 way. At this point there was only cold air coming through the vents. When I revved my engine while it was in neutral , it seemed like revving up past 2500 RPMs caused the temperature to return to normal and the heat to come out as hot as it has ever been. I drove it to my local service shop and got the CEL status. As I drove back, I continued to monitor the temperature gauge. Whenever i noticed it climb up, I would either downshift or rev it up in neutral, and it seemed to stabilize the temperature, and it hardly acted out of the normal today, given the temperature gauge wasn't displacing nearly as much, only between 1/3 and 1/2.

I spoke to a well-experienced mechanic that has served my family and I for years about the same problem that I've described to you, and I mentioned the rev-up trick. He told me he is almost certain that the water pump is the culprit. He has seen the same issue with the same remedy: revving the engine helps it. He described that since it is belt-driven, it correlates to my rev-up trick. When the coolant flow stops because of a faulty pump, the temperature goes up because coolant sits in the engine, and quickly heats up, and the heat will not work. When I rev the engine, the pump seems to work again, and the temperature stabilizes and the heat works. Eroded turbine/faulty pump? Pump working on and off like the heat? This makes a good bunch of sense to me.

I am optimistic that this is the issue. Hopefully it makes sense. THANK YOU AGAIN!

Zed

If your civic is indeed doing 190000 miles, you might as well change the headgasket now, as it will probably be due in another 10K miles or so anyway.

Matt_75

Ok. Good luck with that.

joshua.mills

I would love to fix major issues one after another, but I am going to wait until money isn't a limiting factor. Im sure 10K from now I will be 10K wealthier. Thanks for the suggestion though

Matt_75

BTW, are you using water or 50/50 for the coolant?

joshua.mills

50/50. Always the way to go!

EDIT: I know there is antifreeze in the reservoir, but I can't be too sure if the previous owner watered it down too much or not

Matt_75

Cool. I was just curious.

BTW, if the water pump isn't the problem, please keep us updated.

anibis

When you FIRST checked the coolant in the radiator was it low?

The heater core is the high point of the cooling system and is where air bubbles usually get stuck, most likely from a leaky head gasket. Air in the system can cause the heat to only work when you rev the motor; air blocks coolant from passing until the pressure increases (revving). Honda techs use the heat as one of their first tests when an overheating car comes in, if it doesn't have heat at idle then a. coolant is low b. air in the system.

Bleeding will help an engine with a bad HG, it's only temporary because the leaky HG puts more air in the system when your driving.

Water pump failures are rare in these cars, I've never heard of anything other than a gasket/bearing failure. I've never heard of a pulley slipping on the rod. The impeller+rod are one piece, only place to slip is where the pulley connects to the rod. Of course your car has prob had a timing belt done and maybe bad parts were used. I also HIGHLY doubt the impeller blades have eroded away.

Any excessive cranking/rough idle on the first start of the day?

Matt_75

Nice write up anibis. And I seriously doubt it's the water pump as well. I just didn't want keep trying because you could tell his mind was made up.

I don't even know why people like this come to these forums for information and then do something like this below and ignore everything we try to tell them. I'm guessing they are in denial some how.

joshua.mills

I drove it over the weekend, freeway and city. It only acted up once.

The first time I checked the coolant while my engine was cold it was like an inch or so below where the cap is, and it hasn't moved from there each time I've checked it after(when it's cold). How you described air bubbles trapped in the heater core makes sense, it probably explains the symptom I described earlier, plus the water pump is unlikely the culprit after reading your post. I will have to use the method @Matt_75 mentioned, using air pressure to test the cylinders at my local shop, to see if my head gasket is bad..
And my car starts smoothly from a cold start, and the idle is smooth, seems to run completely normal.

I am not ignoring you, I am glad you want to help me and you are, in fact, helping. I just thought that symptom that came up eliminated the possibility of what you were thinking. Everything you have said is legitimate, and I'm only posting newly acquired information to assist in finding the problem.

It seems likely that I have a bad HG, I just need to get my car to the shop when I get the chance. I will keep you guys posted, much gratitude.

Matt_75

We know you're not, but it feels a little bit like a slap in the face when you start posting like you did about your well experienced family mechanic and going with his opinion after we took the time and effort to explain the problem to you based on your symptoms.

Anyway, water under the bridge. Make sure you get the head checked and machined since it sounds like you overheated several times if the pressure test reveals it's the HG.

Good luck.

joshua.mills

Take it how you like, although I wasn't "going with" anything. I put his opinion there so it could be challenged, which it was. Im sorry if I upset you, I was just giving another point of view, from another mind.

If it turns out to be the HG, i will make sure measures are taken to check the head.

Ill keep you guys posted, thanks.

Matt_75

Nope not upset at all. Just hope you find the problem whatever it may be. Looking forward to the update.

joshua.mills

Thanks for the support man. Just a question, if it is the HG, what should I expect for a bill for around a 60/hr labor rate? and how long would it take before its done?

Matt_75

No idea really. I did the work myself on mine. You'd have to call around to local mechanics and a dealer even. I would imagine ball park would be $600-$1000 for labor and one to two days depending on who's doing the work.

ltruong68

I have the same problem on my 2003 EX. Did you find the problem?

ltruong68

I am having the same problem. Did you find the solution?

ezone

Head gasket is blown

ltruong68

Thank you. I will go on youtube and look for videos on how to diy.

ezone

Look instead for how to diagnose and prove that is really the cause of your problems, before you strip it all apart.


The first post in this thread has tons of info and a couple videos.
https://www.civicforums.com/forums/3...reference.html